Polyurethanes formed by polyaddition of polyisocyanates and polyhydroxyl compounds are largely used as reactive one- or two-component systems as adhesives, sealing materials, decoration coatings, protective coatings and floorings. Thereby, they have to meet very different requirements. Of particular importance are the storage stability prior to application, the potlife and processing viscosities during the application and the reactivity, the mechanical and thermal properties as well as the chemical resistance after the application. For coatings and floor coverings the aesthetic properties are often of decisive importance. The surfaces, dependent on the application must have different degrees of gloss, from glossy and satiny to mat. The surfaces must be completely free of deficiencies, thus defects such as pinholes, pigment floating, Bernard cells, rub-out-effects, bad levelling, craters, bubbles and others are not acceptable. It is generally known that achieving all technical requirements on the one hand necessitates an adjustment of all components of a formulation, an the other hand it is largely dependent on the used polyhydroxyl compounds.
In order to achieve the above mentioned requirements, the constituents used in the formulation must be compatible with each other. Besides the exclusively technical requirements imposed on said products also economical aspects are of great importance. The relation between the price and the performance of a product is often decisive for its possible use. For polyurethane pastes the costs of the whole formulation are largely determined by the costs of the polyhydroxyl compounds used. Additionally, the whole environmental impact of the product receives growing attention. In several countries, the legislation intends to reduce the environmental impact of commercial products in order to protect the environment and the raw material resources. For this reason, some governments require environmental impact assessment (EIA) reports to be submitted to the authorities before introducing new products into the market. In this context, minimizing the formation of carbon dioxide during the whole life cycle of a product (from production to waste disposal) is of utmost importance.
This can be achieved e.g. by extensive use of recycled or naturally growing raw materials.
In two component polyurethane formulations (component A: polyol, component B: isocyanate) for coatings (floor coverings, protective coatings, corrosion inhibiting coatings) a large variety of different polyhydroxyl compounds such as e.g. polypropylene glycol, polyethylene glycol, polyester, polycarbonate etc. are applicable.
It is known that the use of castor oil as polyol component results in materials with good properties (particularly good deficiency free surfaces, long potlife followed by fast curing). Usually castor oil is used together with other polyethylene oxide-based polyols or polypropylene oxide-based polyols
The GDR (former German Democratic Republic) patent No 125 037 describes the production of polyurethane pastes, for instance a mixture of recycled, i.e. alcoholized, polyethylene terephthalate (PET) and castor oil. However, the use of castor oil together with aromatic polyester polyols as a physical mixture, as it is for example described in the above mentioned patent, is not suitable for the production of polyurethane coatings and floor coverings, since castor oil is chemically incompatible with the polyester leading to a separation. Thus, poor mechanical properties (low abrasion and scratch resistances) are obtained, particularly, however, poor surface properties (floating of pigments, surface defects) and insufficient storage stability (sedimentation or the fillers). This is due i.a. to the chemical incompatibility of the polyol components. Also, the processability is insufficient for the use as coatings and floor coverings due to the high viscosity of the binders described in the above mentioned patent.
Processes for recycling PET materials for the production of plastics are known for along time already. The U.S. Pat. No. 5,252,615 of Sherwin-Williams Co. describes the reaction of alcoholysis products of PET with e.g. acids under formation of acid group containing products with different acid group contents. Such products are particularly suitable for the production of aqueous, radically curing acrylic coatings The publication of Eastman Chemicals No N-292 B describes the production of unsaturated polyester resins out of PET. The use of conversion products of polyethylenterephthalate, PET, and polyols (de-polymerized PET) as raw material for the production of PU-compositions (particularly foams) is also known. For example the U.S. Pat. No. 4,223,068, No 4,417,001 and No 4,048,104 describe the production of hard polyurethane foams made out of recycled PET. The use of such binders, however, is not suitable for the formulation of coatings and floor coverings. The use of such aromatic polyols mostly leads to brittle products with poor aesthetic and insufficient processability.
The problem to be solved by the present invention thus was to produce a novel kind or polyhydroxyl compounds having a minimal negative impact on the environment allowing to better meet the sometimes contradictory requirements expected from polyurethane compositions, particularly coatings and floor coverings, than the state-of-the-art compounds do and having a more advantageous environmental impact. Said contradictory requirements include e.g. excellent mechanics, good chemical resistance, short processing times and good storage stabilities. In particular, the goals of the present invention were the production of polyhydroxyl compounds which can be synthesized at least in part out of low-cost, recycled raw material, possibly in combination with naturally regrowing raw materials, and the formulation of floor coverings and coatings enabling
excellent mechanical properties such as high tensile strengths and high modulus in tension at high elongation, good abrasion resistances, high compressive strengths, high scratch resistances PA1 defect-free, aesthetic surfaces PA1 good chemical resistance. PA1 A is oxygen or nitrogen, PA1 X is 1 or 2 and y=0 or 1, whereby for A=N x+y is 2 and whereby for A=0 x is 1 and y is 0, PA1 R.sub.1 is an aromatic polyester segment, particularly the polyester segment of the condensation product of an aromatic diacid and an optionally substituted aliphatic glycol, PA1 R.sub.2 is an optionally OH substituted, aliphatic, cyclic or aromatic C.sub.1 -C.sub.8 hydrocarbon chain or an optionally OH substituted dialkylether, trialkylether or tetraalkylether group or an optionally OH substituted ester or polyester of at least one aliphatic or aromatic carboxylic acid with aliphatic alcohols and/or glycols, PA1 R.sub.3 is a saturated or unsaturated C.sub.11 -C.sub.21 alkylradical substituted by at least one OH group, and PA1 R.sub.4 is hydrogen or hydroxyalkyl PA1 R.sub.3 is CH.sub.3 (CH.sub.2).sub.5 --CHOH--CH.sub.2 --(CH).sub.2 --(CH.sub.2).sub.7 -- PA1 Q is ##STR5## and p is 3.